Scaffold



(No Model.)

P. B. eILBRETI-I.

SCAFFOLD.

Patented July 26, 1892.

' UNITED STATES PATENT OFFICE.

FRANK B. GILBRETH, OF BOSTON, MASSACHUSETTS.

SCAFFOLD.

SPECIFICATION forming part of Letters Patent No. 479,591, dated July 26,1892. Application filed February 13, 1892. vSerialllo. 421361. (Nomodel.)

To all whom t may concern,.-

Be itknown that I, FRANK B. GILBEETH, of Boston, county of Suffolk,State of Massachusetts, have invented an Improvement in Scaffolds, ofwhich the following description, in connection with the accompanyingdrawings, is a specication, like letters and figures on thedrawingsrepresenting like parts.

In the erection of buildings it is frequently customary for the masonsto work from scaffolds erected upon the lioor or oors of the buildinginside the walls, the scaffold being raised from time to time asnecessary to bring the masons into proper working position with relationto the rising walls.

This invention relates to scaffolds of this class, and has for itsobject to simplify and improve the same.

The prime feature of this invention is a `scaffold having threeplatforms located, re-

spectively, at three different levels, the middle or stock platformbeing the highest, the other two platforms being arranged at oppositesides of and below the stock-platform, one for the masons and the otherfor the laborers, the platform for the masons being at such a levelbelow the stock-platform that the masons may conveniently pick up thestock as necessary, while the laborers platform is arranged still loweror at such a level that a hod of stock may be dumped upon thestockplatform by the laborer without dropping the stock or bending toavoid dropping it. These three platforms will preferably be supported byframes carried by a single line of standards, which are thus calculatedto offer the least inconvenience to the masons in picking up the stock,such standards forming a second important feature of this invention.

One part of this inventiontherefore consists in a scaffold having threeplatforms arranged at three different levels, the middle platform beingthe highest, substantially as will be described; also,in a scaffold, thecombination, with a series of frames and platforms supported thereby, ofasingle line of supporting-standards for the said frames, substantiallyas will be described.

Other features of the invention will be hereinafter described, andpointed out in the claims.

In the drawings, Figure 1 represents in perspective a scaffold embodyingthis invention; Fig. 2, an end view of the same; Fig. 3, ase'ction onthe dotted -line a; fr, Fig. 2; Fig. 4, a detail face view of a portionof one of the standards, showing the lifting-jack in position; Fig. 5, asectional view of the same on the dotted line oc', and Fig. 6 asectional detail illustrating a modified construction to be described. I

Referring to the drawings, A A represent horses, each of which consists,as herein shown, of a vertical standard a, having a foot d', suitablybraced by the diagonal braces a2, these horses being arranged in asingle' line along the wall being erected. The standards a of each horsepreferably consist of two members 1 2, separated from each other by asuitable spacing-block 3 to receive between them the frames B, havingsupports for three different platforms. port-s a frame B, consisting, asherein represented, of the vertical side bars b b, connected by thethree cross-bars b b2 b3, all of which pass through the space betweenthe members l 2 of the standard, the said cross-bars being preferablycut away, as at 5, to receive the inner member of the standard whichthus acts as a guide to prevent tipping of the frame when in use. Theupper cross-bars b of the frame B serve to support the planksconstituting the stock-platform c, a plank being laid upon thecross-bars at each side of the standards a, the latter thus projectingupwardly the middle of the platform. The opening left between the twoplanks thus laid upon the top cross-bars b may be closed by planks p,extending between the standards, as shown. The lower cross-bars b3 areextended at one side beyond the side bars b to support the planksconstituting the laborers platform c', while the intermediate cross-barsb2, located, preferably, at or about midway between the upper and lowercross-bars, are also extended at one end, but at that side of the frameopposite the extended ends of the lower cross-bars b3, said intermediatecrossbars serving as supports for the masons platform c2.

By reference to Fig. l it will be seen that thc laborers platform c',reached by a ladder or inclined plane, is at such a level below thestockplatform c that the laborer may dump Each standard a sup- ICO a hodof stock from his shoulder upon the stock-platform without dropping thestock or bending to deposit it without dropping, thus effecting aconsiderable saving in time, and the laborer is obliged' to travel' upthe ladder or inclined plane no higher than is absolutely necessary todeposit his load. On the other hand it will be seen by reference to Fig.l that the masons platform is at such a level intermediate the stock andlaborers platform that a mason at work on the platform may pick up hisstock most readily, as the stock-platform is arranged at the mostconvenient level for him. Again, the single line of standards a,projecting, as they do, through the middle of the stock-platform c, arein such positions that they offer the least possible inconvenience tothe masons and laborers while engaged in their work.

The frames B may be moved up and down in the standards ct to the desiredheight to best accommodate the mason at work by any suitable means ordevices, the frames being held in proper fixed position by pins f,i'nserted through suitable holes f in the standards a beneath thecross-bars of the frames, as shown. In practice, however, I prefer toemploy lifting-jacks to raise the frames B and the platforms carriedthereby, and referring to Figs. `l, 4, and 5 I have shown lifting-jacksarranged for this purpose, the jack being of any suitable construction.I prefer, however, to employ jacks of substantially the constructionshown, they consisting of a base fm, in which the toothed lifting-bar mis movable by a suitable pinion actuated by a handle m2. The bases ofthe jacks are recessed at 6 to receive pins n, inserted through holes inthe standards a, while the upper ends or hubs of the lifting-bars fm areshaped to straddle the pins f, which support the frames l), carrying theplatforms, the said hubs being preferably extended at one side, as at10, beneath the frames B to better sustain the weight of the workmenupon the scaffold as the latter is lifted.

lVhen it is desired to raise the platforms, the jacks will bemanipulated by the handles fm2 to raise the frames B slightly to takethe weight of the frames and the platforms thereon off from the pinsf,when the pins will be withdrawn from the standards and the jacks furthermanipulated to raise the frames B up to the next set of pin-holes, whenthe pins f will be inserted in the said pin-holes to hold the frames andthe platforms thereon in adj usted position. The lifting-bars of thejacks will then be tripped and permitted to return to their normalcontracted condition, the pins n withdrawn, and the jack raised to thenext set of pin-holes and the pins n again inserted to sustain the jacksin their new positions in readiness to raise the platforms another stepwhen necessary.

While I prefer to employ jacks arranged as shown, lyet I do not restrictmy invention to this particular method of raising platforms.

In practice two or more horses may be arranged in line in front of awall, the planks forming the platforms being strung along from one horseto another, and end braces h may be hinged to the upper ends or edges ofthe upper diagonal braces a2, attached to the horses to prevent endwisemovement of the scaffold. By hinging the end braces h to the ends of theupper braces a2, as shown in Fig. Ll, the end braces h may be turned ineither direction, either upwardly against the standard or downwardlyagainst the braces.

The space-blocks 3 may be removed when it is desired to remove theframes B from the horses, as for transportation or storing.

This invention is not limited to the particular shape and constructionof the various parts herein shown, as the same may be varied, theprincipal features of this invention being, rst, a scaffold having threeplatforms arranged at different levels, and, second, a series ofplatform-supporting frames and a single line of supporting-standardstherefor.

The standards, instead of being formed of two members, may, if desired,be formed of a single member o only, the platform-supporting frame beingsuitably carried by them, as shown in Fig. 6.

l. A scaffold having a central platform and two platforms arranged atdifferent levels on opposite sides of and below said central platform,substantially as and for the purposes set forth.

2. A scaffold comprising a single line of standards andsupporting-frames thereon carrying two platforms at different levels andupon opposite sides of the said standards and a third platform locatedabove the said platforms, substantially as described.

3. A scaffold comprisinga series of horses, each having a singlevertical standard, a series of frames carried by and adjustable on saidstandards, each frame having three platform-supports arranged each at adifferent level, one of the supports being above and between the othertwo,substantially as described.

4. In a scaffold, a horse having a vertical standard composed of twomembers secured to each other and constituting a single standard, and aframe supported entirely by Said standard and fitted to move verticallybetween and guided by said members, the said frame having supports forthree platforms arranged at differentlevels, substantially as described.j

5. A scaffold comprising a series of horses. each having a singlevertical standard, and a series of platform-supporting frames carried byand adjustable on said standards, each supporting-frame having supportsfor two or more platforms arranged at different levels, substantially asdescribed.

6. In a scaffold, a series of horses arranged in line, each having asingle vertical standard, a platform-supporting frame carried solely byeach standard, and a lifting-jack sustained IOO IIO

IZO

by a pin inserted in the standard and acting against and to lift thesupporting-frame carried by said standard, substantially as described.

7. In a scaffold, aseries of horses having vertical standards comprisingtwo members each, platform-supportin g frames arranged between saidmembers and supported by pins extending through said members, combinedwith lifting-jacks for the said frames, arranged between the members ofthe said standards and supported upon pins passed through said members,substantially as described.

8. In a scaold, a series of horses comprising vertical standards, feeta', and diagonal braces a?, and platform-supporting frames carried bysaid standards, combined with the end braces h, hinged to the ends ofthediagonal braces d2, whereby they may be turned upwardly against thestandards or outwardly against the braces, substantially as described.In testimony whereof I have signed my name to this specification in thepresenceof two subscribing witnesses.

FRANK B. GILBRETH.

Witnesses:

FREDERICK L. EMERY, FRANCES M. NOBLE.

